鄱阳湖核心流域地区城市地表形态的异质性r对地表温度的影响研究

摘要

鄱阳湖是中国最大的淡水湖,其生态保护受到高度关注.以鄱阳湖流域核心地区为研究对象,基于Landsat-8 OLI遥感影像和已更新至2015年江西省地理国情普查房屋建筑矢量数据,进行城市建筑形态及地表温度(LST)的空间分布、变化特征的定量化研究,且深入分析建筑形态与LST之间的相互影响关系.此外,利用高分辨率的3D建筑物栅格数据进行天空开阔角系数(SVF)的计算.结果表明,(1)湖区整体以低层低密度、低层高密度建筑形态为主,市级地区以中层高密度建筑、高层中密度建筑为主;低层低密度、低层高密度建筑主要分布在经济发达程度一般、城镇化率较低的县乡级地区.(2)湖区2005年和2016年10月的地表温度均低于5月,且低层低密度较为松散的建筑形态是引起湖区热环境变化最主要的建筑形态,高层高密度建筑形态的所在地区地表温度较为稳定.(3)建筑高度和建筑密度与地表温度之间呈正相关性,2016年5月地表温度与建筑高度、建筑密度的相关性系数分别为0.447和0.691,10月为0.486和0.841.从相关系数可知,建筑密度对地表温度的影响程度高于建筑高度.(4)实验区在晴好天气昼间,SVF值范围为0.06～0.79,主要频率在0.2～0.5之间.5月SVF值与地表温度之间的相关性系数为0.044,不存在明显的线性相关性;10月两者之间Pearson相关性系数为0.606,相关性较高.SVF值较小的区域,建筑分布密集,阻碍大气对流,且阻挡长波辐射能量,不易于地表热辐射的扩散.地表形态的异质性会导致高低各异的地表温度及不同程度的地表温度变化,建筑高度和建筑密度要素对鄱阳湖核心流域地区地表温度具有直接的影响,且建筑密度的影响更大.%Poyang lake is the largest freshwater lake in China, and its ecological protection has been highly concerned. In this paper, the core area of the Poyang Lake Basin is selected as the research object. Based on the Landsat-8 OLI remote sensing image and building vector data of the geographical conditions census which has been updated to 2015 in Jiangxi Province, the spatial distribution and change characteristics of the urban building form and land surface temperature (LST) is quantitatively studied, and the relationship between architectural form and LST is deeply analyzed. Then, the Sky View Factor (SVF) is calculated by using high-resolution 3D building raster data. (1) The lake district is dominated by low-rise low-density and low-rise high-density buildings, and the city-level areas are dominated by middle-level high-density buildings and high-rise high-density buildings. Low-rise low-density and low-rise at high-density buildings are mainly distributed in counties and rural areas with low economic development and low urbanization rate. (2) The LST of the lake district in October 2005, 2016 is lower than that in May, and the low-rise low-density buildings are the most important architectural form that causes the change of thermal environment in the lake area. The LST of high-rise high-density buildings area are stable. (3) There is a positive correlation between building height, building density and LST. The correlation coefficient between LST and building height, building density in May 2016 was 0.447 and 0.691 respectively, which was 0.486 and 0.841 in October. According to the correlation coefficient, the influence of building density on LST is higher than that of building height. (4) In sunny days, the range of SVF in the experimental area is from 0.06 to 0.79, and the main frequency is between 0.2 and 0.5. The correlation coefficient between SVF and LST was 0.044 in May, and there was no obvious linear correlation. Pearson correlation coefficient was 0.606 in October, and the correlation was high. In the region with lower values of SVF, dense buildings obstruct atmospheric convection, block long wave radiation and make it difficult to diffuse the surface heat radiation. The heterogeneity of surface morphology can result in different LST and varying degrees of LST changes. The building height and building density factors have a direct impact on the LST of the Poyang lake core area which is easily affected by the construction density.